The plans to open the chapel to worshippers of all faiths are being considered by senior parliamentary officials together with Helen Grant, the equalities minister.

The scheme was first proposed by Chris Bryant, the Labour MP and a vocal supporter of the Government's plans to legalise same-sex marriage, in a debate on the legislation.

In response, Mrs Grant pledged to see how the Government could “assist” the MP and has asked officials in the Department for Culture, Media and Sport to examine the proposals.

Separately, Mr Bryant wrote a letter wrote to John Bercow, the Speaker of the House of Commons asking him to help lift the restrictions on the chapel so allow gay marriages to be held there.

The Labour MP said he had already received a reply, expressing support for the plans, from Mr Bercow.

The speaker has also asked Lt Gen David Leakey, the official within Parliament known as 'Black Rod’ who is responsible for the chapel, to look into the issue.

Lt Gen Leakey is now consulting “relevant bodies” about the proposals, including the Church of England, as well as officials in Mrs Grant’s department.

Mr Bryant, a former Anglican vicar, said the chapel was already being used to hold Catholic masses, adding that it seemed “odd” not to formally open it to worshippers from other religions and Christian denominations, including those who will conduct same sex marriage.

He added: “St Mary Undercroft has been many things in its time. It was the Speaker’s dining room and before that Cromwell used it to stable his horses.

“It is a bit odd that we have no place for people of other faiths to worship. If we have got over this hurdle with Catholic masses being celebrated there it seems odd not to allow services of other denominations to be held there.”

The proposals could see all Christian symbols removed from the room, which is currently used by MPs and peers to hold wedding and christening ceremonies as well as other services.

They have been questioned by the Rev Rose Hudson-Wilkin, the Commons chaplain, who has been involved in discussions over the chapel’s future.

St Mary Undercroft, is a “royal peculiar”, meaning that it comes under the direct authority of the Queen, as the Supreme Governor of the Church of England.

This means, the Queen would have to give permission for a change to allow non-Anglican religious services to be carried out in there.

Mrs Hudson-Wilkin said: “The query that Mr Bryant has put through is complex and we can’t just send out a response to say this is what it is going to be. Although it is a royal peculiar it still comes under the banner of the Church of England, so there are a number of issues to be considered.”

But she added: “There is a space on the Parliamentary estate where people of other faiths have access. The chapel is the chapel.

“When I go to a country of another religion I don’t say to them 'you have got to fit that to my requests because I am in your country’. I simply would not expect them to say, 'well this is a mosque but let’s make it into something else.’ We respect other faiths and we make provisions and that is what we have done.”

A multi-faith prayer room was recently installed on the Parliamentary estate, although it is in a nearby office building run by the House of Lords rather than in the Palace of Westminster itself.

St Mary Undercroft was completed under King Edward I in 1297 and was used for worship by the Court and the Royal household. Because of its location below ground it was one of the few areas of the Palace of Westminster to survive a fire in 1834 which destroyed both Houses of Parliament.

It is a popular marriage venue for MPs. In 1997 then leader of the Opposition, William Hague, married his wife Ffion in the chapel and in 2002 Charles Kennedy, then leader of the Liberal Democrats, wed Sarah Gurling. A few months later Mr Bercow wed his wife Sally in the crypt.